Here are links to a couple of round the world trips that I was just looking at:

The first is Remi Desfontaine's trip (in french) that he just completed earlier this year, having followed a northern hemisphere route via turkey, iran, central asia, china and then from hawaii across the States.

http://www.monde-a-velo.com

The second is a Iranian couple who were just featured on today's BBC online and they're site is here

http://www.rmc4peace.com/iran.htm

Enjoy,

Jules